Adding ! fails to suppress warning

[jcouv]

The sample below shows two problems:
1. T is actually constrained to a class type, so return null should be ok
2. Adding ! did not supress this warning

public class C {
    public T M<T>()  where T : C {
        return null!; // warning CS8625: Cannot convert null literal to non-nullable reference or unconstrained type parameter.
    }
}

[cston]

! should suppress the warning (that is a valid bug), but since T is constrained to a reference type, the method could be declared as returning T? to avoid the warning.

[jcouv]

This seems to have been fixed already (sharplab).
Never mind. Still repros on my local branch.